Multiple barrier filter apparatus

TECHNICAL FIELD

0001The present invention relates generally to filtering systems and in particular to a filtering apparatus that includes multiple filtering elements.

BACKGROUND OF THE INVENTION

0002For at least the last 15 years, there have been several configurations of “under-sink” reverse osmosis (RO) systems designed to improve the quality of a relatively small amount of water to be used for drinking and cooking by a homeowner. A few examples of such systems are described in U.S. Pat. Nos. 4,650,586 and 4,629,568 both of which are owned by the assignee of the present invention and incorporated herein by reference.

0003An objective of typical under sink reverse osmosis systems is to decrease the total dissolved solids (TDS) of the supplied city or well water and thereby improve the taste, odor or chemical makeup of the water. These under the sink reverse osmosis systems can be upgraded to include additional unit processes to pre-treat the incoming water for chlorine or sediment removal prior to the RO unit. This pre-treatment improves the operation and prolongs the life of the RO membrane. In addition pre-treatment further polishes the water produced by the RO membrane to remove both trace organics that might cause taste issues and small molecular weight contaminants that might pass through or be poorly rejected by the RO membrane. Therefore today there are many versions of RO units that effectively remove or reduce specific unwanted ionic contaminants and or organics to improve the quality of the water for the use of the homeowner.

0004There is increasing concern that some of the water supplies, both from wells, surface waters or even municipalities may, from time to time contain unwanted microbiological contaminants such as pathogens, that may be harmful when ingested by people, especially persons with immune system deficiencies.

0005While the pore size of the common RO membrane is sufficiently small to prevent the passing of microbiological contaminants, testing over the years has shown that the RO unit alone cannot consistently meet the relatively stringent requirements to be classified a “microbiological purifier” as defined in EPA in the “Guide Standard and Protocol for Testing Microbiological Water Purifiers” (1987 revision). It is believed that the reason for this is the imperfections in the RO membrane itself or in the methods of bonding the membrane together at the ends of the assemblies. While there are several methods available to deal with such concerns, such as boiling the water for several minutes or adding anti-pathogen agents like iodine to the water, most of these are not convenient and/or may make the water less pleasant to drink. Ultraviolet light filters that neutralize contaminants by exposure to certain wavelengths of light are also known in the art. These filters suffer from several practical drawbacks including the fact that they rely on electricity to function and also require relatively complex controls to ensure that water is not overheated due to extended exposure to the light.

SUMMARY OF THE INVENTION

0006By adding multiple barrier filter capabilities to a traditional under sink RO unit, improved removal of microbiological contaminants, unwanted ionic species, and organics can be achieved.

0007According to the present invention a filter apparatus for treating water containing particulate or microbial contaminants is provided. The filter apparatus includes a first filter element disposed within a first sealed outer housing and in fluid communication with a first inlet port and a first outlet port. The first filter element is capable of treating water at a first flow rate and is adapted to remove contaminants that are larger than a first contaminant size. A second filter element is disposed downstream of the first filter element in fluid communication with a second inlet port and a second outlet port. The second filter element is capable of treating water at a second flow rate higher than the first flow rate and is adapted to remove contaminants that are larger than a second contaminant size. An accumulating vessel is placed in fluid communication with the first outlet port and the second inlet port for storing water that has been treated by the first filter element prior to treatment by the second filter element.

0008For a preferred embodiment that is directed to removing microbial contaminants, the first filter element is a virus filter membrane capable of removing contaminants larger than 0.01 micron and the second filter element is a bacteria filter membrane capable of removing contaminants larger than 0.1 micron.

0009In an exemplary embodiment that facilitates under sink mounting, the second filter element is disposed within the first sealed outer housing. According to a feature, at least one of the first and second filter elements is generally cylindrical in shape and has a central void and the water flowing to and from the other of the first and second filter element flows within the central void. According to another feature, the first inlet port, first outlet port, second inlet port, and second outlet port are disposed on a single surface of the sealed outer housing. According to yet another feature, a flow limiting device is place in fluid communication with the first filter element for controlling the flow of water to the first filter element.

0010According to an embodiment a pretreatment filter is placed in fluid communication with the first inlet port for removing relatively large contaminants prior to treatment by the first and second filter elements. According to an embodiment, a post filter is placed in fluid communication with the accumulating vessel and adapted to remove contaminants that originate in the accumulating vessel or may have passed through prior filters. In an embodiment, a cross flow membrane filter, such as a reverse osmosis filter, is placed in fluid communication with the first inlet port. In a preferred embodiment, a check valve is placed on a concentrate line of the cross flow membrane filter.

0011In an exemplary embodiment, a flow monitor is placed in fluid communication with the first outlet port to monitor an amount of water that has been treated by the filter apparatus. According to a feature, the flow monitor is operable to discontinue the flow of water through the filter apparatus when a predetermined amount of water has been treated by the filter apparatus. In one embodiment, the flow monitor is part of the post filter.

0012In a preferred embodiment, the filter apparatus includes a check valve in fluid communication with the second outlet port and downstream of the second filter element for preventing backflow of contaminated water into the filter apparatus. According to a feature of the invention, the check valve is a duck bill check valve installed in a treated water dispensing faucet in fluid communication with the second outlet port and through which treated water flows out of the filter apparatus. According to another feature the check is made of an antimicrobial material.

0013Another exemplary embodiment of the inventive filter apparatus is adapted to treating water containing microbial contaminants. A viral membrane filter is disposed within a first sealed outer housing and in fluid communication with a first set of inlet and outlet ports. The viral membrane filter is adapted to remove viral contaminants. A bacterial filter membrane is disposed downstream of the viral membrane and in fluid communication with a second set of inlet and outlet ports, the bacterial filter membrane adapted to remove contaminants.

0014In an embodiment that facilitates under sink mounting, the bacterial filter element is disposed within the first sealed outer housing. According to a feature, at least one of the viral and bacterial filter membranes is generally cylindrical in shape and has a central void such that water flowing to and from the other of the viral and bacterial filter membrane flows within the central void. According to another feature, the first inlet port, first outlet port, second inlet port, and second outlet port are disposed on a single surface of the sealed outer housing.

0015According to an embodiment a pre-treatment filter is placed in fluid communication with the first inlet port for removing relatively large contaminants prior to treatment by the first and second filter elements. According to an embodiment, an accumulating vessel is placed in fluid communication with the first outlet port to store water that has been treated by the viral filter membrane prior to being treated by the bacterial filter membrane. According to a feature a post filter is placed in fluid communication with the accumulating vessel and adapted to remove contaminants that originate in the accumulating vessel or pass through prior filters. In an embodiment, a cross flow membrane filter is placed in fluid communication with the first inlet port.

0016In an exemplary embodiment, a flow monitor is placed in fluid communication with the first outlet port to monitor an amount of water that has been treated by the filter apparatus. According to a feature, the flow monitor is operable to discontinue the flow of water through the filter apparatus when a predetermined amount of water has been treated by the filter apparatus. In one embodiment, the flow monitor is part of the post filter.

0017In a preferred embodiment, the filter apparatus includes a check valve in fluid communication with the second outlet port and downstream of the second filter element for preventing backflow of contaminated water into the filter apparatus. According to a feature of the invention, the check valve is a duck bill check valve installed in a treated water dispensing faucet in fluid communication with the second outlet port and through which treated water flows out of the filter apparatus. According to another feature the check is made of an antimicrobial material.

0018According to a preferred embodiment, a filter apparatus for removing contaminants from water containing microbial contaminants includes a cross flow membrane filter for removing a significant amount of relatively large contaminants from the water. A viral membrane filter is disposed within a first sealed outer housing and in fluid communication with cross flow membrane filter that is adapted to remove viral contaminants and a bacterial membrane filter is in fluid communication with the viral membrane filter that is adapted to remove bacterial contaminants. According to a feature of this embodiment, the cross flow membrane filter is a reverse osmosis filter. An additional feature is an accumulating vessel disposed between and in fluid communication with the viral membrane filter and the bacterial membrane filter for storing water that has been treated by the viral membrane. Preferably, the bacterial membrane filter is disposed in the first sealed outer housing and at least one of the viral and bacterial filter membranes is generally cylindrical in shape and has a central void and such that water flowing to and from the other of the viral and bacterial filter membrane flows within the central void.

0019According to an embodiment of the invention, a treated water dispensing faucet for dispensing water that has been treated to remove contaminants includes a conduit for directing the flow of treated water from a filtration system to a dispensing station. The conduit has a first end connected to the filtration system and a second end that includes an orifice that opens to the dispensing station. A check valve is mounted to the second end for preventing the back flow of contaminants to the filtration system. According to a feature, the check valve is a duck bill check valve that includes antimicrobial material. According to yet another feature, a valve shield member substantially encloses the check valve for preventing contact between foreign objects and the check valve.

0020According to another feature of the invention, a filter cartridge is disclosed that includes a housing that defines first and second isolated regions within the housing. The first region includes a first filter and a flow path extending from a first inlet to a first outlet. The second region defines a flow path extending between a second inlet port and a second outlet port. The ports are arranged in a substantially linear, side-by-side relationship and are adapted to establish fluid connections between the filter cartridge and a manifold forming part of a water treatment system as the filter cartridge is installed into its operative position. In the preferred embodiment, the first region includes a viral filter and the second region includes a bacterial filter.

0021Although the construction illustrated in the preferred embodiment includes a viral filter and a bacterial filter located in the same replaceable housing, it should be understood that aspects of this invention can be applied to systems in which separate viral and bacterial filter units are utilized, as opposed to having both filters in one housing.

0022These and other objects, advantages, and features of the invention will be better understood from the accompanying detailed description of preferred embodiments of the invention when reviewed in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

0023The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which:

0024<figref idref="DRAWINGS">FIG. 1</figref> is a schematic representation of a water filtration system constructed in accordance with the present invention;

0025<figref idref="DRAWINGS">FIG. 2</figref> is a front plan view of a water filtration system depicted in <figref idref="DRAWINGS">FIG. 1</figref>;

0026<figref idref="DRAWINGS">FIG. 3</figref> is a cross section view of a water dispensing faucet in accordance with a feature of the present invention;

0027<figref idref="DRAWINGS">FIG. 4</figref> is a cross section of a multiple barrier microbial filter of the water filtration system shown in <figref idref="DRAWINGS">FIG. 2</figref>;

0028<figref idref="DRAWINGS">FIG. 5</figref> is a cross section of a multiple barrier anti-microbial filter of the water filtration system shown in <figref idref="DRAWINGS">FIG. 2</figref> and as seen from the plane indicated by the line <b>5</b>—<b>5</b> in <figref idref="DRAWINGS">FIG. 2</figref>;

0029<figref idref="DRAWINGS">FIG. 6</figref> is an exploded view of the multiple barrier anti-microbial filter;

0030<figref idref="DRAWINGS">FIG. 7</figref> is another sectional view of the anti-microbial filter substantially similar to the cross section shown in <figref idref="DRAWINGS">FIG. 4</figref>, but showing the filter detached from the water filtration system;

0031<figref idref="DRAWINGS">FIG. 8</figref> is an exploded view of the water filtration system shown in <figref idref="DRAWINGS">FIG. 2</figref>;

0032<figref idref="DRAWINGS">FIG. 9</figref> is a perspective view of a manifold that forms part of the water filtration system;

0033<figref idref="DRAWINGS">FIG. 10</figref> is a partially schematic representation showing a bottom elevational view of the manifold shown in <figref idref="DRAWINGS">FIG. 9</figref> and also illustrating fluid connections between a storage tank and faucet;

0034<figref idref="DRAWINGS">FIG. 11</figref> is a top plan view of the manifold shown in <figref idref="DRAWINGS">FIG. 9</figref>;

0035<figref idref="DRAWINGS">FIG. 12</figref> is a sectional view of the manifold as seen from the plane indicated by the line <b>12</b>—<b>12</b> in <figref idref="DRAWINGS">FIG. 11</figref>;

0036<figref idref="DRAWINGS">FIG. 13</figref> is a fragmentary sectional view of the manifold as seen from the plane indicated by the line <b>13</b>—<b>13</b> in <figref idref="DRAWINGS">FIG. 10</figref>; and,

0037<figref idref="DRAWINGS">FIG. 14</figref> is a top elevational view of a locking handle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

0038<figref idref="DRAWINGS">FIG. 1</figref> illustrates schematically a water treatment system <b>10</b> for removing particulate and microbial contaminants from water. The water treatment system <b>10</b> designed for mounting under the sink in a typical residential kitchen and for dispensing treated water from a system dedicated faucet <b>70</b> including a flow control valve <b>71</b> having an operating handle <b>71</b><i>a</i>. The system includes a pre-filter <b>20</b> such as Kinetico part number 9309 and a reverse osmosis filter <b>30</b> (such as that disclosed in U.S. Pat. No. 4,650,586, assigned to assignee of the present invention and incorporated herein by reference) placed in series to remove a majority of contaminants typically found in residential water supplies. While an RO filter is described herein, it will be apparent to one of skill in the art that any cross flow membrane filter such as a nanofiltration unit, an ultrafiltration unit, or a microfiltration unit can be used to practice the present invention. The pre-filter <b>20</b> filters out entrained solids to reduce the incidence of plugging of the internal membrane (not shown) in the reverse osmosis filter <b>30</b> and is believed to prolong the life of the reverse osmosis filter. A check valve <b>79</b> on the concentrate line of the RO filter prevents entry of contaminants into the system via the concentrate line.

0039A multiple barrier microbial filtration unit <b>40</b> that includes a viral filter membrane <b>40</b><i>a </i>and a bacterial membrane <b>40</b><i>b </i>polishes the water that exits the reverse osmosis filter <b>40</b> to remove microbial pathogens from the water. The RO filter <b>30</b> removes a large percentage of the contaminants that remain in the water after treatment by the pre-filter <b>20</b> to prevent clogging of the relatively fine pores found in the viral and bacterial membrane filters <b>40</b><i>a</i>, <b>40</b><i>b</i>. In addition, the RO filter serves as a flow limiting device that controls the flow to the viral membrane filter <b>40</b><i>a </i>thereby facilitating operation of the viral filter membrane at a sufficiently slow flow rate that optimizes contaminant removal based on a relatively small filter membrane size.

0040A storage tank <b>50</b> such as is placed in fluid communication with an outlet of the viral membrane <b>40</b><i>a </i>to store water that has been treated by the viral membrane. The placement of the storage tank <b>50</b> after the viral membrane <b>40</b><i>a</i>, but before the bacterial membrane <b>40</b><i>b</i>, improves the flow capacity of the overall system. This is because the flow capacity of the viral filter membrane <b>40</b><i>a </i>is significantly lower than the desired flow rate for the faucet <b>70</b>. The flow capacity of the bacterial membrane <b>40</b><i>b </i>is higher than that of the viral membrane and as such, water can be pulled from the storage tank <b>50</b> on demand by the faucet and be treated by the bacterial membrane <b>40</b><i>b </i>to filter out contaminants originating from the storage tank or have passed through prior filters at a flow rate that is acceptable in terms of providing flow at the faucet. The bacterial membrane <b>40</b><i>b </i>also serves as a protection against bacterial contamination that may enter the system at the faucet <b>70</b>. A post filter <b>60</b>, such as the one disclosed in U.S. Pat. No. 4,698,164 assigned to the assignee of the present invention and incorporated herein by reference, is positioned between the viral membrane <b>40</b><i>a </i>and the bacterial membrane <b>40</b><i>b </i>to provide an additional filter to protect against contaminants that originate in the storage tank or have passed through prior filters. In addition, the post filter <b>60</b> serves as a fluid monitor by monitoring the amount of water flowing to the anti-bacteria membrane <b>40</b><i>b </i>and shutting off flow via an internal flow control mechanism (not shown) once a predetermined amount of water has been treated. This shut off feature prevents system usage once the filter element performance has degraded to an unacceptable level.

0041<figref idref="DRAWINGS">FIG. 2</figref> is a front plan view of a water treatment system <b>10</b>. A mounting bracket <b>12</b> with mounting tabs <b>14</b> for connecting the bracket under a typical residential sink supports a manifold assembly <b>13</b>. The manifold assembly <b>13</b> includes water conduit and connection points for replaceable cartridge portions of the various filter units that make up the system: the pre-filter <b>20</b>, the reverse osmosis filter <b>30</b>, the multiple barrier microbial filtration unit <b>40</b>, and the post filter <b>60</b> having a flow monitoring head <b>61</b> that gives an indication of the amount of water that has been treated by the current cartridge and shuts of flow when a predetermined amount of water has been treated. An outlet connection (to be described) is connected to a line <b>314</b> that runs to the faucet <b>70</b> (shown in <figref idref="DRAWINGS">FIGS. 1</figref>, <b>3</b> and <b>10</b>). While this particular combination of pre-filter, reverse osmosis filter, and post filter is discussed for the purposes of this description, other combinations of filters that may or may not include these filters may be used in conjunction with the multiple barrier microbial filtration unit in the practice of the present invention.

0042Referring now to <figref idref="DRAWINGS">FIG. 3</figref>, a cross sectional view of the faucet <b>70</b> is shown. A water conduit or spout <b>72</b> terminates at one end in a dispensing orifice <b>74</b>. A check valve <b>75</b> such as a duck bill check valve supplied by Vernay Laboratories, Inc. of Yellow Springs, Ohio as part number VA 4295 is held adjacent to the dispensing orifice <b>74</b> by a protective shield or spout tip <b>78</b> that encloses the check valve <b>75</b> and is pressed or threaded onto the water conduit <b>72</b>. Due to the presence of bacterial contaminants in the kitchen and bathroom sinks to which the faucet is mounted, it is beneficial to employ this check valve to protect the system from contaminants in the air, splashes, or objects found in the sink. To further enhance the contamination reducing capability of the system, the check valve <b>75</b> may be molded of a material that includes an antimicrobial treatment. The check valve <b>79</b> (<figref idref="DRAWINGS">FIG. 1</figref>) on the concentrate line may be a similar duck bill type valve appropriately sized for the concentrate line. Alternately, conventional ball-type check valves may be used.

0000Multiple Barrier Microbial Filtration Unit

0043<figref idref="DRAWINGS">FIG. 4</figref> illustrates details of the multiple barrier microbial filtration unit <b>40</b> that filters microbial contaminants from the water. The microbial filtration unit <b>40</b> is connected to an associated manifold portion <b>15</b> that forms part of the manifold assembly <b>13</b>, with screws, tabs, or other appropriate means. The manifold <b>15</b> provides appropriate fluid paths to route the water into and out of the various components of the microbial filtration unit <b>40</b>. The internal workings of the manifold will be further explained below. An inlet <b>41</b> defined by the manifold <b>41</b> routes water from the reverse osmosis filter <b>30</b> to the microbial filtration unit <b>40</b> via a first input port <b>110</b> that is in fluid communication with the microbial filtration unit <b>40</b>

0044The microbial filtration unit <b>40</b> includes a sealed outer housing indicated generally as <b>45</b> having an end cap <b>43</b> that is welded to the housing after assembly of the filter elements <b>40</b><i>a </i>and <b>40</b><i>b </i>therein. It is believed that enclosing the viral filter membrane <b>40</b><i>a </i>and the bacterial filter membrane <b>40</b><i>b </i>in a single cartridge eliminates overall system performance variations that might be caused by housing the filter membranes separately and in addition the single cartridge facilitates removal and replacement by the end user. The viral filter membrane <b>40</b><i>a </i>engages the end cap <b>43</b> to locate the element such that first fluid channel <b>114</b> is defined between the inner wall of the housing and the outer surface of the membrane <b>40</b><i>a</i>. The viral filter membrane <b>40</b><i>a </i>is cylindrical in shape and includes a pleated membrane filter element disposed concentrically about a tubular supporting structure and encased in an outer protective jacket having fluid access openings therein. Filters such as the viral filter membrane are known in the art. An example of the viral filter <b>40</b><i>a </i>is manufactured by Pall Corporation of New York under part number VABV20P0A. The viral filter membrane <b>40</b><i>a </i>engages and sits upon an interior connector <b>44</b> having a fluid path (to be described in connection with <figref idref="DRAWINGS">FIG. 6</figref>) for incoming water to enter into the first fluid channel <b>114</b> through a first inlet port <b>110</b> and through a first inlet conduit <b>1</b><b>12</b>. The water flows to a first interior filter channel <b>115</b> by passing through the filter membrane <b>40</b><i>a </i>to remove contaminants and treated, outgoing water exits the viral filter membrane <b>40</b><i>a </i>through a first outlet conduit <b>116</b> that is connected to the manifold <b>15</b> by a first outlet port <b>118</b>. O rings <b>135</b>, <b>131</b> seal the interface between the viral filter membrane <b>40</b><i>a </i>and the interior connector <b>44</b>, and the interior connecter <b>44</b> and the outer housing <b>45</b>, respectively.

0045The manifold <b>15</b> provides a fluid path from the first outlet port to both the storage tank <b>50</b> (<figref idref="DRAWINGS">FIG. 1</figref>) and the bacterial filter <b>40</b><i>b </i>such that water will flow to the storage tank unless the tank is empty and there is a demand for water at the faucet <b>70</b>. In this case, the water from the viral filter membrane <b>40</b><i>a </i>will travel directly to the post filter <b>60</b> and on to the bacterial filter <b>40</b><i>b </i>as described in further detail below. The storage tank enhances the overall output capability of the system because it buffers the flow reducing effect of the small pore size needed to filter out small, virus sized particles removed by the viral filter membrane <b>40</b><i>a. </i>

0046The post filter <b>60</b> (<figref idref="DRAWINGS">FIGS. 1 and 2</figref>) includes a carbon filter (not shown) that removes contaminants from the water that may be have passed through the prior filters or are a result of the environment of the storage tank. In addition, as already described, the post filter serves as a fluid monitor to shut off flow through the system once a predetermined quantity of water has been treated. Replacement of the cartridge on the post filter resets the monitor so that flow can be reestablished.

0047Referring again to <figref idref="DRAWINGS">FIG. 4</figref>, the bacterial filter membrane <b>40</b><i>b </i>is cylindrical in shape and includes a pleated membrane filter element disposed concentrically about a tubular supporting structure and encased in an outer protective jacket having fluid access openings therein. Filters such as the bacterial filter membrane are known in the art. An example of this type of filter is manufactured by Pall Corporation of New York under part number NA7AA00P0A. The bacterial filter membrane <b>40</b><i>b </i>engages the interior manifold <b>44</b> to locate the membrane and form a second fluid channel <b>121</b> through which water can flow from a second inlet port <b>127</b> and through the bacterial filter membrane <b>40</b><i>b </i>to a second outlet channel <b>122</b> that is in fluid communication with a second outlet port <b>130</b>. The outlet port <b>130</b> connects to the manifold <b>15</b> which provides a connection to the faucet <b>70</b>.

0048As can be seen from the foregoing description, by providing multiple barrier microbial filtering capabilities in conjunction with a cross flow membrane filter, a filtration system capable of significantly reducing microbial contaminants from water can be provided in a unit sized to fit beneath a residential sink.

0049<figref idref="DRAWINGS">FIGS. 6–14</figref> illustrate other features and constructional details of the present invention. In the preferred embodiment, the multiple barrier filtration unit <b>40</b> is configured as a replaceable cartridge. Referring, in particular, to <figref idref="DRAWINGS">FIG. 6</figref>, the filtration unit <b>40</b> includes the outer housing <b>45</b> (previously described) that is closed at its bottom end by the end cap <b>43</b>. An assembly of components is captured within the housing <b>45</b> and end cap <b>43</b>. The components include the viral and bacterial filter units <b>40</b><i>b</i>, <b>40</b><i>a </i>(previously described). The upper part of the viral filter <b>40</b><i>b </i>is secured to an adapter <b>200</b> which defines three upwardly directed sockets <b>202</b>, <b>204</b>, <b>206</b>. Referring also to <figref idref="DRAWINGS">FIG. 7</figref>, these three sockets sealingly engage nipples <b>202</b><i>a</i>, <b>204</b><i>a</i>, <b>206</b><i>a </i>which depend downwardly and are integrally formed with a top <b>45</b><i>a </i>of the housing <b>45</b>. Associated O-rings <b>207</b> (<figref idref="DRAWINGS">FIG. 6</figref>) seal the interface between the sockets and nipples.

0050Referring to <figref idref="DRAWINGS">FIGS. 4–7</figref>, a water receiving or inlet chamber <b>219</b> is defined between the top of the adapter <b>200</b> and the underside of the cartridge housing. As seen best in <figref idref="DRAWINGS">FIG. 7</figref>, the inlet port <b>250</b><i>a </i>communicates with the inlet chamber <b>219</b>. Water to be treated is received in the chamber <b>219</b> and travels to the second fluid channel <b>121</b> via slots <b>200</b><i>a </i>(shown in <figref idref="DRAWINGS">FIG. 6</figref>) formed in the adapter <b>200</b>.

0051As described above, the bottom of the viral filter <b>40</b><i>b </i>sits on the connector <b>44</b>. The connector includes an upstanding, integrally molded pipe assembly <b>220</b><i>a </i>that defines the fluid passages <b>112</b>, <b>116</b> (see also <figref idref="DRAWINGS">FIG. 4</figref>). A rigidizing rib <b>221</b> is molded between the pipe structure. A pair of nipples <b>206</b><i>b</i>, <b>204</b><i>b </i>sealingly engage the sockets <b>204</b>, <b>206</b> defined in the cap <b>200</b>. Associated O-rings <b>222</b> seal the interface between the nipples and sockets. Also integrally formed in the connector <b>220</b> is a cross passage <b>230</b> which communicates the passage <b>112</b> (defined by the pipe assembly <b>220</b><i>a</i>) with the region <b>114</b> (see also <figref idref="DRAWINGS">FIG. 4</figref>) that surrounds the viral filter <b>40</b><i>a</i>. The communication is indicated by the dashed line <b>230</b><i>a </i>in <figref idref="DRAWINGS">FIG. 7</figref>. In particular, the cross passage <b>230</b> communicates the channel <b>112</b> with the outside of a downwardly depending flange <b>220</b><i>c </i>forming part of the connector <b>220</b>. The outside of the flange <b>220</b><i>c </i>communicates with the region <b>114</b>, i.e., the outside of the viral filter <b>40</b><i>a. </i>

0052The bottom of the viral filter <b>40</b><i>a </i>sits on a filter spacer <b>234</b> which, in turn, fits within and sealingly engages the bottom cover <b>43</b> of the filter housing. Turning now to <figref idref="DRAWINGS">FIG. 7</figref>, the filter unit <b>40</b> is configured to be relatively easily replaceable without the need for special tools. As previously described, the water treatment system includes a mounting bracket <b>12</b> to which the fluid manifold <b>15</b> is secured. In particular and referring also to <figref idref="DRAWINGS">FIG. 8</figref>, the manifold <b>15</b> includes mounting apertures <b>15</b><i>a </i>through which fasteners extend in order to bolt the manifold to the underside of the bracket <b>12</b> by means of mounting holes <b>15</b><i>b. </i>The manifold portion <b>15</b> defines internal fluid passages for communicating the internal fluid paths defined by the filter unit <b>40</b> with other components of the system. In particular, and referring to <figref idref="DRAWINGS">FIGS. 7 and 9</figref>, the manifold <b>15</b> defines four downwardly depending nipples <b>250</b>, <b>252</b>, <b>254</b> and <b>256</b>. The cartridge housing <b>45</b> defines four corresponding sockets <b>250</b><i>a</i>, <b>252</b><i>a</i>, <b>254</b><i>a </i>and <b>256</b><i>a </i>which are configured to receive and sealingly engage the associated manifold nipples <b>250</b>, <b>252</b>, <b>254</b>, <b>256</b>. The sockets <b>252</b><i>a</i>, <b>254</b><i>a</i>, <b>256</b><i>a </i>connect to and may form part of the nipples <b>202</b><i>a</i>, <b>204</b><i>a</i>, <b>206</b><i>a</i>, respectively. The housing sockets include associated O-rings <b>260</b> and pressed-in retainers <b>262</b> for holding the O-rings within the sockets <b>250</b><i>a</i>, <b>252</b><i>a</i>, <b>254</b><i>a</i>, <b>256</b><i>a </i>shown in <figref idref="DRAWINGS">FIG. 7</figref>).

0053The housing <b>45</b> also includes integrally molded upstanding, retaining lugs <b>270</b>, as well as a pair of stabilizing standoffs <b>272</b>. The standoffs <b>272</b> include reduced diameter portions <b>272</b><i>a </i>at their upper ends. To install the cartridge, the cartridge is positioned beneath the supporting bracket <b>12</b> and attached manifold <b>15</b>. By raising the cartridge upwardly, towards the bracket, the four depending nipples <b>250</b>, <b>252</b>, <b>254</b>, <b>254</b> of the manifold <b>15</b> enter the associated sockets <b>250</b><i>a</i>, <b>252</b><i>a</i>, <b>254</b><i>a</i>, <b>256</b><i>a </i>while concurrently, the upwardly extending lugs <b>270</b> enter and extend through complementally shaped holes <b>270</b><i>a </i>formed in the bracket <b>12</b>. In addition, the standoffs <b>272</b> engage the underside of the bracket <b>12</b> with the reduced diameter portions <b>272</b><i>a </i>extending into complementally shaped holes <b>273</b> formed in the is bracket <b>12</b> (see <figref idref="DRAWINGS">FIG. 8</figref>).

0054To secure the filter unit <b>40</b> to the bracket <b>12</b>, a molded retainer clip <b>280</b> is removably secured to the lugs <b>270</b>. The detailed construction of the retainer clip <b>280</b> is shown in <figref idref="DRAWINGS">FIG. 14</figref>. In particular, each lug <b>270</b> includes an aperture <b>281</b> near its upper end (shown in <figref idref="DRAWINGS">FIG. 7</figref>). The retaining clip <b>280</b> includes a pair of spaced apart, split pins <b>280</b><i>a </i>molded integrally with a handle-like portion <b>280</b><i>b</i>. The split pins <b>280</b><i>a</i>, in their relaxed state, define a diameter greater than the diameter of the holes <b>281</b> and are compressed as they are inserted into the lugs <b>270</b>. The pins <b>280</b><i>a </i>include detents or protrusions <b>283</b> which engage the rear surface of the lugs <b>270</b> and inhibit withdrawal of the retainer <b>280</b>.

0055As the manifold nipples <b>250</b>, <b>252</b>, <b>254</b>, <b>256</b> enter the cartridge sockets <b>250</b><i>a</i>, <b>252</b><i>a</i>, <b>254</b><i>a</i>, <b>256</b><i>a</i>, they are sealingly engaged by the associated O-rings <b>260</b> located within the sockets and, thus, fluid leakage between the nipples and the sockets is inhibited while still providing a releasable, fluid connection.

0056<figref idref="DRAWINGS">FIG. 10</figref> illustrates an exploded view of the water treatment system and, in particular, shows the various filter units and the manifold assembly <b>13</b> and bracket <b>12</b> to which the filter units are releasably attached. A cover <b>290</b> preferably overlies the bracket <b>12</b> and hides from view the top of the bracket and the fluid connections, manifold and retainers for the filter units and cartridges.

0057Referring to <figref idref="DRAWINGS">FIGS. 9–13</figref>, the construction of the manifold portion or segment <b>15</b> (to which the filter unit <b>40</b> is attached) is illustrated. In particular, <figref idref="DRAWINGS">FIG. 10</figref>, which is a view of the underside of the manifold <b>15</b>, illustrates schematically the fluid flow paths defined by the manifold <b>15</b> along with the connections to the storage tank <b>50</b> and faucet <b>70</b>. The manifold <b>15</b> includes a conduit segment <b>300</b> which includes a pair of O-ring grooves <b>300</b><i>a </i>adapted to receive suitable O-rings. The conduit segment <b>300</b> is adapted to be received in an input or inlet socket of the filter <b>60</b>. A socket-like connection <b>302</b> is adapted to receive a conduit that connects the socket <b>302</b> with the output of the filter unit <b>60</b>. Another socket-like connection <b>304</b> forms part of the manifold <b>15</b> and is adapted to sealingly connect to a nipple which defines an output from the RO filter unit <b>30</b>. The manifold <b>15</b> also defines a pair of conduit connections <b>310</b>, <b>312</b>. The conduit connection <b>310</b> is intended to connect with a conduit that connects the tank <b>50</b> with the manifold <b>15</b>. The connector <b>312</b> connects the manifold <b>15</b> with a feed conduit <b>314</b> (see <figref idref="DRAWINGS">FIG. 1 and 10</figref>) for the faucet <b>70</b>.

0058As seen best in <figref idref="DRAWINGS">FIG. 10</figref>, the passages <b>330</b>, <b>332</b> and <b>338</b> are at least partially formed by tubular segments <b>316</b><i>a</i>, <b>316</b><i>b</i>, <b>316</b><i>c</i>, <b>316</b><i>d. </i>During manufacture of the manifold <b>15</b>, the right ends (as viewed in <figref idref="DRAWINGS">FIG. 10</figref>) of the tubular segments are sealed. In the illustrated embodiment, a blocking plate <b>318</b> is suitably secured to the right ends of the tubular segments <b>316</b><i>a</i>, <b>316</b><i>b</i>, <b>316</b><i>c</i>, <b>316</b><i>c </i>using conventional attachment methods, such as welding or adhesively bonding.

0059The nipple <b>250</b>, which serves as an input to the bacterial filter <b>40</b><i>b</i>, is connected to the socket <b>302</b> by a passage defined by the manifold and illustrated schematically by the dashed line <b>330</b>.

0060The nipple <b>256</b>, which communicates the output from the viral filter <b>40</b><i>a </i>with the storage tank <b>50</b> and with the input to the post filter <b>60</b> is connected to the conduit connector <b>310</b> and the conduit segment <b>300</b> by communicating internal passages <b>332</b><i>a</i>, <b>332</b><i>b</i>. With this configuration, a significant amount of water can be stored by the tank <b>50</b>, rather than only processing water as it is dispensed by the faucet <b>70</b>.

0061The nipple <b>254</b>, which communicates filtered water from the RO unit <b>30</b> to the input side of the viral filter <b>40</b><i>a</i>, is connected to the socket <b>304</b> by an internal passage <b>336</b>. The nipple <b>252</b>, which is connected to the output side of the bacterial filter <b>40</b><i>b</i>, communicates with the conduit connector <b>312</b> by an internal passage <b>338</b>. As noted above, the conduit connector <b>312</b> is connected to a feed conduit <b>314</b> for the faucet <b>70</b>.

0062<figref idref="DRAWINGS">FIGS. 12 and 13</figref> illustrate additional details of the passages molded within the manifold <b>15</b> which are illustrated schematically in <figref idref="DRAWINGS">FIG. 10</figref>. It should be understood, however, that alternate configurations for the manifold portion <b>15</b>, as well as the passages molded within the manifold, can be made while still providing the fluid connections and functions of the illustrated embodiment and are, therefore, contemplated by the present invention.

0063In the preferred embodiment, the retaining lugs <b>270</b> are disposed in a parallel relationship and are rectangular in cross-section. The standoffs <b>280</b> are located in a spaced apart relationship and are disposed at a 12:00 and 6:00 position with respect to the lugs <b>270</b> which are located at a 9:00 and 3:00 position. In the preferred and illustrated embodiment, the sockets <b>250</b><i>a</i>, <b>252</b><i>a</i>, <b>254</b><i>a</i>, <b>256</b><i>a </i>formed in the housing <b>45</b> which receive the nipples <b>250</b>, <b>252</b>, <b>254</b>, <b>256</b> are located in a juxtaposed positions and have mutually parallel axes. It should be understood, however, that the positioning of the lugs <b>270</b>, standoffs <b>272</b> and sockets <b>250</b><i>a</i>, <b>252</b><i>a</i>, <b>254</b><i>a</i>, <b>256</b><i>a </i>may be changed without substantially changing their functional purposes. The sockets <b>250</b><i>a</i>, <b>252</b><i>a</i>, <b>254</b><i>a</i>, <b>256</b><i>a </i>may, for example, be spatially oriented on the top of the cartridge housing <b>45</b> and be adapted to engage similarly spaced manifold nipples.

0064It should also be noted that the water treatment system illustrated in the drawings is sized for residential use. It should be understood, however, that the principles of this invention can be applied to much larger water treatment systems that could be put to commercial uses. Those skilled in the art would recognize that larger filter units and conduits would be needed in order to sustain the types of flow rates that would be required for commercial applications.

0065Although the present invention has been described with a degree of particularity, it is the intent that the invention include all modifications and alterations from the disclosed design falling within the spirit or scope of the appended claims.